1. Technical Field
The present invention relates to a method for lifting of components of a wind energy installation to the installation height.
2. Prior Art
It is known that the dimensions of modern wind energy installations are becoming ever larger. Some wind energy installations are being installed with hub heights of well over a hundred metres. These dimensions result in various difficulties.
One particular problem is that the individual components of the wind energy installation, for example the generator, must be lifted to the required installation height when the installation is being installed. It is known for heavy-lift cranes or large cranes to be used for this purpose, whose jibs have a considerable length and are designed for considerable forces. The costs which are incurred for the use of such cranes are immense.
It is also known for a lifting device to be installed in the area of the tower head of the wind energy installation, in particular on the machine support. This in general has a winch, onto which a hoisting cable is wound. This hoisting cable is let out downwards until it is close to the ground, when required. There, components to be lifted are connected to the cable, and are then lifted up by winding the cable onto the winch.
However, the maximum lifting height of these lifting devices is in general not sufficient to lift large components, which must be positioned adjacent to or on the machine support of the wind energy installation, for example the installation generator, to the required installation height. This is because the lifting height of a lifting device such as this is generally limited or defined by deflection rollers over which the respective hoisting cable is let out downwards. These deflection rollers are normally attached to the machine support. Since the uppermost areas of the component to be lifted can at best be lifted to immediately below the deflection roller, it is not possible to lift the component or at least subareas of it to installation heights above the machine support. By way of example, a ring generator must be connected to a shaft journal, which is mounted on the machine support, when the installation is being installed. For this purpose, the ring generator must first of all be pushed centrally onto the shaft journal. In order to allow it to be pushed onto the shaft journal, the ring generator must first of all be raised to a corresponding installation height centrally in the axial direction in front of the shaft journal. During this process, the upper areas of the ring generator must correspondingly be moved to a height above the shaft journal, and therefore above the machine support. This cannot be done using the described lifting device.
In order to improve the lifting height of the described lifting devices which are arranged on the machine support, complex crane devices are in some cases installed according to the prior art on the machine support, which have crane jibs directed obliquely upwards. In this case, this adds only the height between the free end of the crane jib on the one hand and the machine support on the other hand to the lifting height. However, a crane jib which is directed obliquely upwards such as this is subject to the problem that it has to support considerable loads and withstand considerable forces while large components are being lifted. This in turn requires installations whose costs even exceed the costs of a mobile heavy-load crane or large crane arranged on the ground.